High-tension cable



March 18, 1930- w. c. HAYMAN 1,751,403

HIGH TENSION CABLE Filed Dec. 14, 1928 Inventor'. William C. Hagfmom,bgm/Wwm/ Y v His Attorney,

stars imma rarer carica MEME C. BECKMAN, F SGHENEGTDY, NEW YORK,ASSIGNOR TO GENERAL ELEG- TRIC COMPANY, A CORPORATION OF'NEW YORKnrenrnnsron canta application l'ed December le, 1928. Serialfto.325,991.

' underground conduits, although it is not to be construed asnecessarily limited `to such use.

lt is the practice at the present time to provide these cables withelectrostaticshields to prevent corona eiiect Which are locatedbetWeen'the outesurface of the conductor insulation and the enclosingmetal sheath, which is commonly made shields are made of very thin metalin the form of Wrapped-on ribbon, and are easily torn or stretched, orboth, .in leading the cable. rlhe ribbons are perforated at suitablyspaced intervals t-Q permit the insulating fluid to freely pass throughfrom one side to the other so as inspre complete impregnation oi" thepaper or other insulaq tion. These perforations further weaken theribbon and increase the manufacturing diiiiculties. lt is also thepractice with multiple conductor cables, especially of the shielded typeto provide an additional Wrap ping of steel tape in the form oi a band,which is Wrapped on over the shielding ribbon.

ln order that the metal ribbon may per form its function .as ashield,vit mustbe in electrical communication, and 4preferably over aportion of each and every turn or Wrap, With the lead sheath. "Where Vametal band is provided in addition, electrical contact must bemaintained'from ribbon to lthe band and from it-to the sheath.

"llo guard against injury to the ribbon or band, or both, as the casemay be, in the manufacturing operation it is the practice to Wind overthe ribbon or band a temporary layer of paper and also a longitudinallyextending cord, termed a rip-cord, by means of which the outer temporarylayer of paper may be ripped olil at some point the entrance of thecable into the lead press. Such an arrangement while generallysatisfactory in results requires an operator Whose 'job it is to seethat all of the outside paper covering i: removed before the cable isleaded, and also to see that paper does not accumulate and getinto thepress.- e bViOuSly, this extra of lead. These the process ci adjacenttov operation increases the cost or the cable and is generallyobjectionable.

ln accordance With my invention an arrangement of parts is providedwhereby the4 use of temporary and removable external Wrapper of paper tohold the ribbon or band in firm contact With the insulation on theconductorto prevent injury is avoided and-in this'inanner am able todispense with one voperation and one operator in the manufacture ot'cable of the character described. l am also able to'ensure the properseating and binding of the ribbon or band in place.

F or a consideration o-what l believe to be novel and my invention,attention is directed to the accompanying description and claimsappended thereto. A

ln the drawing ,which is illustrative of my inventiomligure l is alongitudinal section, partly in elevation, or" a piece or single conductor cable; Figure 2 is an end view or the same Alligure 8 is alongitudinal section, partly` in elevation, of aV piece ci,three-conductorcable; Figure {iis an end view oai-the same; .and Figure5 is a diagrammatic illust conductors which are stranded in any suitablemanner to form a cable. Surrounding the conductor and tightly Wrappedthereon are concentric turns, or layers oi paper 57, said paper beingWound spirally as is the common practice. .The shielding ribbon 8, maybe Wound directly on the insulation or theremay be interposed betweenthe two an eXtra layer of a good grade of to form a bed 9, for theribbon, somewhat elastic. Either directly on the conductor insulation oron the bed, when the latter is provided, there is simultaneously Woundby machine to give the necessary tension and uniformity, the perforatedshielding ribbon 8,l and a lstrip of good tough paper 10. Thearrangement is suchtliat approximately one-half of the paperstrip'overvliesapproaimately one-half bf the outer sur tough paperandwhich is approximately one-half ofthe adjacent turn or wrap of theshielding ribbon. The adjac'ent turns or wraps of the ribbon areseparated at their edges'by approximately the thickness of the paperwhere it passes from the undersidea of one turn to the outer surface ofthe adjacent turn. This abutting arrangement is the best, although, insome cases, it will be satisfactory to have the edges of the ribbonseparated by a somewhat greater amount, provided that the electrostaticstress on the impregnating fluid between the edges or elsewhere is notthereby made too high.

As a result of. the overlapping arrangement, one part of each turn ofthe paper strip is bound down by a metal ribbon and the other partlbinds down the adjacent turn of said metal ribbon. The paper is of sucha width .and so positioned that the metal ribbon is exposed betweenturns as indicated at 11, Fig. 1to make electrical contact or ground vwith the sheath 12. The paper .should be as thin as possible, consistentwith the strength required. -In most, if not all cases, it will besatisfactory to use the same'- kind of paper that is used for theoutside layers on the conductor.

As before stated, the metal ribbon is thin, being, for example, of the4order of from three. to ive mils in thickness.

it will be found that the peripheral surface is smooth and flat. This isdue to the fact that the exposed part of the thin metal rib-l 'ble withlead as indicated at 12, itshould be done in such manner that the papercovers the entering edges of the successive turns of the .metal ribbonthereby protecting v.them from injury. 1

In Figure 5 1s illustrated diagrammatically the arrangement of the metalribbon 8 and' the wound-on strip of insulation 10. -It will i, theribbon and extends through the small be observed that one part of thestrip is under ribbon and covers a part of the adjacent turn. Inpractice, the space between edges of the v metal ribbon is made equal tothe thickness of the paper. 7 indicatesv the insulation on the conductorand 7a indicates a paper wrapping to form a bed when such a bed is foundto be desirable.

Referring now to Figures?) and 4, which indicate a suitable arrangementfor a multiple conductor cable, 13 indicates the copper .or otherconductors -which are covered by wound-on insulation 14' of which paperis a good example., The peripheral surface of each conductor covering iswound with a ribbon 15, to form an electrostatic shield, which,

After the ribbon nand paper tape are tightly .wound in place,

artefice to attain the best results, is perforated in order to permitthe'fluid insulation to freely Ipenetrate the paper. The ribbons on theseveral conductors, when assembled as shown, are 1n contact one wlth theother. The space 1n the center between the conductor coverings is filledby a suitable filler 16, and the ner are wrapped with a thin metalcoveringA which to distinguishit from the other metal coverings willbereferred to as a band 20. This band may be made of thin steel orequivalent metal having the necessary tensile strength tofirmly lholdthe individual conductors intheir-assembled Irelation and preventspreading. yThis band and a strip of paper 21 are wound simultaneouslyover the conductors in the manner described in connection with theperforated ribbon 8 of Fig. 1. That is to say each turn of the papertape is'partly coveredby one turn of the band,

--the other part of the tape covering'a part of' the turn of theadjacent wrapping of the band.- In winding, the shield 15 is wound onsay with a right-hand spiral', while the steel 00 words, the two metalcoverings cross each other -instead of occupying similar positions.

band is -wound in a left-hand spiral'. In other This facilitates theseveral operations, and at the same time results in a smoother andbetter finished cable. After the band is applied, the Acable is fedthrough a press and given a lead" covering 22. When this is done allofthe shields as well as the bindingband 'are in' electrical.'communication and are grounded to the sheath.

The insulation on the cable illustrated is effect impregnated with asuitable insulating compound and isgenerally known as a'solid cable,

. vbt-th t' ll lf'bl t space between edges of adjacent turns of the u emven lon '1S equa y app ma e O cables ofother types in which definitechannels are provided for oil or other .insulation for simplicity asbeing made of metal,..\b/ut it is to be understood that in thisdesignation i I aim to include materials'which have only a metalizedsurface and not Y one composed wholly of. metal. v` f I have referred tolead as the protective or outside covering or sheath and by this term 'Iinclude all coverings in which lead is the principal element, althoughit may be alloyed with other' materials to give it greater strength.

-What I claim as-new and desire to' secure by Letters Patent of theUnited States, is:

1. A cable comprising a conductor, insulation thereon, a yspirallyWrapped ribbon of metal, a protective strip which underlies a portion ofeach turn of the ribbon and also overlies a portion of the peripheralsurface of the turns orsaid ribbon, and a protective metal coveringWhich is in electrical communication with said metallic ribbon.

2. A cab-le comprising a conductor, insulation thereon, a thin ribbon ofmetal which is spirally Wound thereon, non-metallic means which overliesone edge and a portion of each turn of said metai ribbon, and underliesa portion of an adjacent turn, and a protective metal covering which isin electrical communication With said metallic ribbon.

3. A cable comprisinga conductor, insulation thereon, a coveringcomprising a thin ribbon of metal Wound thereon, theturns beingpositioned side by side, a thin strip of insulation which separates theedges of the turns adjacent turns,

"tion thereon, an electrostatic shield comp of the metal strip byextending through the space between them, one part of the insulationunderlying one turn of the metal and the other portion partly overlyingan adjacent turn, and a protective metal covering which IiDs inelectrical communication with said rib-A 4. A cable comprising aconductor, insulation thereon, a covering comprising a thin strip ofperforated metalwound thereon, a thin strip of paper which partlyunderlies the turns of the metal strip and partly overlies them byextending between the ed es of said paper forming a yie ding bed for themetal so that the exterior presents a smooth surface, and a protectingcovering made of lead which is in electrical communication with thelturns of the strip.

5. A cable comprising conductors, insulaa ris ing a spirally woundmetallic ribbon, 1nsulating material which also is spirally Wound, saidmaterial being partly under onel turn of the. ribbon and partly over anadjacent turn, a metal band to prevent the conductors from spreading,the ribbon and band being in electrical contact, and a metal coveringfor the cable which is in electrical' Contact with the band.

6. A cable comprising conductors, electrostatic shields for theconductors, a spirally wrapped band which prevents theA conductors fromspreading, a strip of paper also spirally wound, each turn of whichunderlies apart of one turn of theband and overlies a partof an adjacentturn, and a metallic sheath. for the whole which snugly fits the bandand is `in electrical contact therewith.

7. A cable comprising conductors, spirally woundv perforated metallicribbon thereon, spirally Wrapped insulation which underlies a partA ofeach turn of the ribbon and overlies a part of each adjacent turn, aband tov revent the conductors from spreading whic 1s also spirallyWrapped over the ribbbon and its insulation,l a spirally Wrapped member'Whichunderlies a part of each turn of the i band and' overlies a partof each adjacent turn, said ribbon and band being in electrical contact,and a lead sheath which is in electrical contact with the band.

8. A cable comprising conductors, insulaction therefor anelectrostaticshield for each conductor, a band which is spirally wrapped around theconductors to prevent them from spreading, insulatin material whichpartly underlies and part y overlies the several turns of the shieldsand band, said band being in electrical communication with all of theshields, and a protective lead covering.

9. A cable comprising conductors, insulation therefor, an electrostaticshield which is spirally Wrappedl around each of the assembledconductors, a metal band to prevent the conductors from spreading andwhich is in electrical contact with the shields, said band beingspirally Wrapped around the shields, but in the opposite direction, sothat the turns of the shields and the band cross each other, means tohold down one edge of each turn of the band, and a protective leadcovering which is in electrical contact with '21,7 lyz'iliam C. Hag/mm,Schenectady, N. Y. HIGH-,Maori CABLE.' Fe'ent A dated Mx-ch 18,-1930.Disclaimer led February 10,1931by the assignee;

Y Heieby disclaims and withdraws that portion of the specieatiqn inwhich it is stated that theeleetrostatc shield in accordance with theinventmn of the 'patent may consist of aaiateriel whieh has only ameaiiizesurace, to page 25-1inesflv19 to ihey'ereferred totheeiecirestatic shield for simiiicity as being'made'of metal,

, it is to'b'e v1111de,rstesii lthat in this designation aim to includemateifials which have.` .v

only a metaiized surfae'and not one composed Wholly of meta.

and Genemi Eieetri Gem/any hereby disclaims the eabie which 'setforthin' the I claims ois-aid patent except when the ribbon or stripconstituting the eleetrust-iic f shield is a metal'ibben or stlip of theorder of three to ivemiis infthickuess. [Ogjiql'Gazette Fama?? 24,1.931.]

